The present invention relates to a low-calorie foodstuff for processed food comprising gel-particles of glucomannan coagulum and also a low-calorie processed food comprising gel-particles of glucomannan coagulum. In particular, the present invention relates to functional foods (the word "functional food" having recently become common) and provides a dietary fiber food component having, e.g., the functions of reducing cholesterol levels, of normalizing blood sugar levels and of normalizing defecation, in addition to being a source of nutrition.
Konjac normally is a Japanese traditional and thermally irreversible food in which konjac flour is swollen with water and coagulated with alkali. A main component of konjac is glucomannan. Glucomannan provides an excellent indigestible dietary fiber of molecules having a molecular weight of several hundred thousand and consisting of glucose and mannose. Konjac has been traditionally used as a food. However, since it requires strong alkalinity in coagulation, an alkali and an alkaline smack remain in konjac, which has restricted the uses of konjac. Konjac coagulum, which is thermally irreversible, is not melted by heating. Konjac coagulum, which is elastic, cannot be made into a paste by grinding.
Generally, the so-called konjac paste comprises an incomplete coagulum of swollen glucomannan. In the past, processes of blending konjac paste with a foodstuff to produce a low-calorie food have been disclosed and all of these processes employ an incomplete coagulum of glucomannan.
The incomplete coagulum of glucomannan, which develops a binding force in a coagulation of konjac paste, can be blended with a different foodstuff. A food blended with konjac paste has essentially the same form as the corresponding original food. However, the glucomannan component of the food gives the food a glue-like touch which also deteriorates the taste of the food. An incomplete glucomannan coagulum blended with a drink thickens the drink so that a light physical property and a touch peculiar to the drink are lost.
On the other hand, a konjac full-coagulum is peculiarly elastic, and thus it is almost impossible to grind and make paste of the konjac full-coagulum. Therefore, konjac full-coagulum is chopped to provide a paste-like foodstuff. The resulting body of gel-particles of konjac full-coagulum has a paste-like appearance but the physical property of the body of gel-particles is different in essence from a paste of incomplete konjac coagulum. The body of gel-particles of konjac full-coagulum has no binding force and blends poorly with a different foodstuff, so that it cannot retain a mixture of the gel-particles and the different foodstuff in the form of a single solid food, even though it does not provide a glue-like touch to deteriorate the taste of the food. Since a food blended with gel-particles of konjac full-coagulum tends to exude water during preservation of the food, the blending capacity of gel-particles of konjac full-coagulum is only 5% of the total amount of the food. Even if gel-particles of konjac full-coagulum are forcibly blended, the blending capacity thereof is only 10% of the total amount of the food. A food with 10% of gel-particles of konjac full-coagulum provides an insufficient low-calorie food.